Commit message: patch 8.2.3564: invalid memory access when scrolling without valid screen

Problem:    Invalid memory access when scrolling without a valid screen.
Solution:   Do not set VALID_BOTLINE in w_valid.
CVE: CVE-2021-3903
CWE: CWE-122
Vulnerability description: vim is vulnerable to Heap-based Buffer Overflow

Project: vim
File: move.c

redraw_for_cursorline(win_T *wp)
{
    if ((wp->w_p_rnu
#ifdef FEAT_SYN_HL
		|| wp->w_p_cul
#endif
		)
	    && (wp->w_valid & VALID_CROW) == 0
	    && !pum_visible())
    {
	if (wp->w_p_rnu)
	    // win_line() will redraw the number column only.
	    redraw_win_later(wp, VALID);
#ifdef FEAT_SYN_HL
	if (wp->w_p_cul)
	{
	    if (wp->w_redr_type <= VALID && wp->w_last_cursorline != 0)
	    {
		// "w_last_cursorline" may be outdated, worst case we redraw
		// too much.  This is optimized for moving the cursor around in
		// the current window.
		redrawWinline(wp, wp->w_last_cursorline);
		redrawWinline(wp, wp->w_cursor.lnum);
	    }
	    else
		redraw_win_later(wp, SOME_VALID);
	}
#endif
    }
}

Project: vim
File: move.c

curs_columns(
    int		may_scroll)	// when TRUE, may scroll horizontally
{
    int		diff;
    int		extra;		// offset for first screen line
    int		off_left, off_right;
    int		n;
    int		p_lines;
    int		width = 0;
    int		textwidth;
    int		new_leftcol;
    colnr_T	startcol;
    colnr_T	endcol;
    colnr_T	prev_skipcol;
    long        so = get_scrolloff_value();
    long        siso = get_sidescrolloff_value();

    /*
     * First make sure that w_topline is valid (after moving the cursor).
     */
    update_topline();

    /*
     * Next make sure that w_cline_row is valid.
     */
    if (!(curwin->w_valid & VALID_CROW))
	curs_rows(curwin);

    /*
     * Compute the number of virtual columns.
     */
#ifdef FEAT_FOLDING
    if (curwin->w_cline_folded)
	// In a folded line the cursor is always in the first column
	startcol = curwin->w_virtcol = endcol = curwin->w_leftcol;
    else
#endif
	getvvcol(curwin, &curwin->w_cursor,
				&startcol, &(curwin->w_virtcol), &endcol);

    // remove '$' from change command when cursor moves onto it
    if (startcol > dollar_vcol)
	dollar_vcol = -1;

    extra = curwin_col_off();
    curwin->w_wcol = curwin->w_virtcol + extra;
    endcol += extra;

    /*
     * Now compute w_wrow, counting screen lines from w_cline_row.
     */
    curwin->w_wrow = curwin->w_cline_row;

    textwidth = curwin->w_width - extra;
    if (textwidth <= 0)
    {
	// No room for text, put cursor in last char of window.
	// If not wrapping, the last non-empty line.
	curwin->w_wcol = curwin->w_width - 1;
	if (curwin->w_p_wrap)
	    curwin->w_wrow = curwin->w_height - 1;
	else
	    curwin->w_wrow = curwin->w_height - 1 - curwin->w_empty_rows;
    }
    else if (curwin->w_p_wrap && curwin->w_width != 0)
    {
	width = textwidth + curwin_col_off2();

	// long line wrapping, adjust curwin->w_wrow
	if (curwin->w_wcol >= curwin->w_width)
	{
#ifdef FEAT_LINEBREAK
	    char_u *sbr;
#endif

	    // this same formula is used in validate_cursor_col()
	    n = (curwin->w_wcol - curwin->w_width) / width + 1;
	    curwin->w_wcol -= n * width;
	    curwin->w_wrow += n;

#ifdef FEAT_LINEBREAK
	    // When cursor wraps to first char of next line in Insert
	    // mode, the 'showbreak' string isn't shown, backup to first
	    // column
	    sbr = get_showbreak_value(curwin);
	    if (*sbr && *ml_get_cursor() == NUL
				    && curwin->w_wcol == vim_strsize(sbr))
		curwin->w_wcol = 0;
#endif
	}
    }

    // No line wrapping: compute curwin->w_leftcol if scrolling is on and line
    // is not folded.
    // If scrolling is off, curwin->w_leftcol is assumed to be 0
    else if (may_scroll
#ifdef FEAT_FOLDING
	    && !curwin->w_cline_folded
#endif
	    )
    {
	/*
	 * If Cursor is left of the screen, scroll rightwards.
	 * If Cursor is right of the screen, scroll leftwards
	 * If we get closer to the edge than 'sidescrolloff', scroll a little
	 * extra
	 */
	off_left = (int)startcol - (int)curwin->w_leftcol - siso;
	off_right = (int)endcol - (int)(curwin->w_leftcol + curwin->w_width
								- siso) + 1;
	if (off_left < 0 || off_right > 0)
	{
	    if (off_left < 0)
		diff = -off_left;
	    else
		diff = off_right;

	    // When far off or not enough room on either side, put cursor in
	    // middle of window.
	    if (p_ss == 0 || diff >= textwidth / 2 || off_right >= off_left)
		new_leftcol = curwin->w_wcol - extra - textwidth / 2;
	    else
	    {
		if (diff < p_ss)
		    diff = p_ss;
		if (off_left < 0)
		    new_leftcol = curwin->w_leftcol - diff;
		else
		    new_leftcol = curwin->w_leftcol + diff;
	    }
	    if (new_leftcol < 0)
		new_leftcol = 0;
	    if (new_leftcol != (int)curwin->w_leftcol)
	    {
		curwin->w_leftcol = new_leftcol;
		// screen has to be redrawn with new curwin->w_leftcol
		redraw_later(NOT_VALID);
	    }
	}
	curwin->w_wcol -= curwin->w_leftcol;
    }
    else if (curwin->w_wcol > (int)curwin->w_leftcol)
	curwin->w_wcol -= curwin->w_leftcol;
    else
	curwin->w_wcol = 0;

#ifdef FEAT_DIFF
    // Skip over filler lines.  At the top use w_topfill, there
    // may be some filler lines above the window.
    if (curwin->w_cursor.lnum == curwin->w_topline)
	curwin->w_wrow += curwin->w_topfill;
    else
	curwin->w_wrow += diff_check_fill(curwin, curwin->w_cursor.lnum);
#endif

    prev_skipcol = curwin->w_skipcol;

    p_lines = 0;

    if ((curwin->w_wrow >= curwin->w_height
		|| ((prev_skipcol > 0
			|| curwin->w_wrow + so >= curwin->w_height)
		    && (p_lines =
#ifdef FEAT_DIFF
			plines_win_nofill
#else
			plines_win
#endif
			(curwin, curwin->w_cursor.lnum, FALSE))
						    - 1 >= curwin->w_height))
	    && curwin->w_height != 0
	    && curwin->w_cursor.lnum == curwin->w_topline
	    && width > 0
	    && curwin->w_width != 0)
    {
	// Cursor past end of screen.  Happens with a single line that does
	// not fit on screen.  Find a skipcol to show the text around the
	// cursor.  Avoid scrolling all the time. compute value of "extra":
	// 1: Less than 'scrolloff' lines above
	// 2: Less than 'scrolloff' lines below
	// 3: both of them
	extra = 0;
	if (curwin->w_skipcol + so * width > curwin->w_virtcol)
	    extra = 1;
	// Compute last display line of the buffer line that we want at the
	// bottom of the window.
	if (p_lines == 0)
	    p_lines = plines_win(curwin, curwin->w_cursor.lnum, FALSE);
	--p_lines;
	if (p_lines > curwin->w_wrow + so)
	    n = curwin->w_wrow + so;
	else
	    n = p_lines;
	if ((colnr_T)n >= curwin->w_height + curwin->w_skipcol / width - so)
	    extra += 2;

	if (extra == 3 || p_lines <= so * 2)
	{
	    // not enough room for 'scrolloff', put cursor in the middle
	    n = curwin->w_virtcol / width;
	    if (n > curwin->w_height / 2)
		n -= curwin->w_height / 2;
	    else
		n = 0;
	    // don't skip more than necessary
	    if (n > p_lines - curwin->w_height + 1)
		n = p_lines - curwin->w_height + 1;
	    curwin->w_skipcol = n * width;
	}
	else if (extra == 1)
	{
	    // less then 'scrolloff' lines above, decrease skipcol
	    extra = (curwin->w_skipcol + so * width - curwin->w_virtcol
				     + width - 1) / width;
	    if (extra > 0)
	    {
		if ((colnr_T)(extra * width) > curwin->w_skipcol)
		    extra = curwin->w_skipcol / width;
		curwin->w_skipcol -= extra * width;
	    }
	}
	else if (extra == 2)
	{
	    // less then 'scrolloff' lines below, increase skipcol
	    endcol = (n - curwin->w_height + 1) * width;
	    while (endcol > curwin->w_virtcol)
		endcol -= width;
	    if (endcol > curwin->w_skipcol)
		curwin->w_skipcol = endcol;
	}

	curwin->w_wrow -= curwin->w_skipcol / width;
	if (curwin->w_wrow >= curwin->w_height)
	{
	    // small window, make sure cursor is in it
	    extra = curwin->w_wrow - curwin->w_height + 1;
	    curwin->w_skipcol += extra * width;
	    curwin->w_wrow -= extra;
	}

	extra = ((int)prev_skipcol - (int)curwin->w_skipcol) / width;
	if (extra > 0)
	    win_ins_lines(curwin, 0, extra, FALSE, FALSE);
	else if (extra < 0)
	    win_del_lines(curwin, 0, -extra, FALSE, FALSE, 0);
    }
    else
	curwin->w_skipcol = 0;
    if (prev_skipcol != curwin->w_skipcol)
	redraw_later(NOT_VALID);

#ifdef FEAT_SYN_HL
    // Redraw when w_virtcol changes and 'cursorcolumn' is set
    if (curwin->w_p_cuc && (curwin->w_valid & VALID_VIRTCOL) == 0
	    && !pum_visible())
	redraw_later(SOME_VALID);
#endif
#if defined(FEAT_PROP_POPUP) && defined(FEAT_TERMINAL)
    if (popup_is_popup(curwin) && curbuf->b_term != NULL)
    {
	curwin->w_wrow += popup_top_extra(curwin);
	curwin->w_wcol += popup_left_extra(curwin);
	curwin->w_flags |= WFLAG_WCOL_OFF_ADDED + WFLAG_WROW_OFF_ADDED;
    }
    else
	curwin->w_flags &= ~(WFLAG_WCOL_OFF_ADDED + WFLAG_WROW_OFF_ADDED);
#endif

    // now w_leftcol is valid, avoid check_cursor_moved() thinking otherwise
    curwin->w_valid_leftcol = curwin->w_leftcol;

    curwin->w_valid |= VALID_WCOL|VALID_WROW|VALID_VIRTCOL;
}

Project: vim
File: move.c

check_top_offset(void)
{
    lineoff_T	loff;
    int		n;
    long        so = get_scrolloff_value();

    if (curwin->w_cursor.lnum < curwin->w_topline + so
#ifdef FEAT_FOLDING
		    || hasAnyFolding(curwin)
#endif
	    )
    {
	loff.lnum = curwin->w_cursor.lnum;
#ifdef FEAT_DIFF
	loff.fill = 0;
	n = curwin->w_topfill;	    // always have this context
#else
	n = 0;
#endif
	// Count the visible screen lines above the cursor line.
	while (n < so)
	{
	    topline_back(&loff);
	    // Stop when included a line above the window.
	    if (loff.lnum < curwin->w_topline
#ifdef FEAT_DIFF
		    || (loff.lnum == curwin->w_topline && loff.fill > 0)
#endif
		    )
		break;
	    n += loff.height;
	}
	if (n < so)
	    return TRUE;
    }
    return FALSE;
}

Project: vim
File: move.c

changed_window_setting_win(win_T *wp)
{
    wp->w_lines_valid = 0;
    changed_line_abv_curs_win(wp);
    wp->w_valid &= ~(VALID_BOTLINE|VALID_BOTLINE_AP|VALID_TOPLINE);
    redraw_win_later(wp, NOT_VALID);
}

Project: vim
File: move.c

set_topline(win_T *wp, linenr_T lnum)
{
#ifdef FEAT_DIFF
    linenr_T prev_topline = wp->w_topline;
#endif

#ifdef FEAT_FOLDING
    // go to first of folded lines
    (void)hasFoldingWin(wp, lnum, &lnum, NULL, TRUE, NULL);
#endif
    // Approximate the value of w_botline
    wp->w_botline += lnum - wp->w_topline;
    if (wp->w_botline > wp->w_buffer->b_ml.ml_line_count + 1)
	wp->w_botline = wp->w_buffer->b_ml.ml_line_count + 1;
    wp->w_topline = lnum;
    wp->w_topline_was_set = TRUE;
#ifdef FEAT_DIFF
    if (lnum != prev_topline)
	// Keep the filler lines when the topline didn't change.
	wp->w_topfill = 0;
#endif
    wp->w_valid &= ~(VALID_WROW|VALID_CROW|VALID_BOTLINE|VALID_TOPLINE);
    // Don't set VALID_TOPLINE here, 'scrolloff' needs to be checked.
    redraw_later(VALID);
}

Project: vim
File: move.c

check_cursor_moved(win_T *wp)
{
    if (wp->w_cursor.lnum != wp->w_valid_cursor.lnum)
    {
	wp->w_valid &= ~(VALID_WROW|VALID_WCOL|VALID_VIRTCOL
				     |VALID_CHEIGHT|VALID_CROW|VALID_TOPLINE);
	wp->w_valid_cursor = wp->w_cursor;
	wp->w_valid_leftcol = wp->w_leftcol;
    }
    else if (wp->w_cursor.col != wp->w_valid_cursor.col
	     || wp->w_leftcol != wp->w_valid_leftcol
	     || wp->w_cursor.coladd != wp->w_valid_cursor.coladd)
    {
	wp->w_valid &= ~(VALID_WROW|VALID_WCOL|VALID_VIRTCOL);
	wp->w_valid_cursor.col = wp->w_cursor.col;
	wp->w_valid_leftcol = wp->w_leftcol;
	wp->w_valid_cursor.coladd = wp->w_cursor.coladd;
    }
}

Project: vim
File: move.c

do_check_cursorbind(void)
{
    linenr_T	line = curwin->w_cursor.lnum;
    colnr_T	col = curwin->w_cursor.col;
    colnr_T	coladd = curwin->w_cursor.coladd;
    colnr_T	curswant = curwin->w_curswant;
    int		set_curswant = curwin->w_set_curswant;
    win_T	*old_curwin = curwin;
    buf_T	*old_curbuf = curbuf;
    int		restart_edit_save;
    int		old_VIsual_select = VIsual_select;
    int		old_VIsual_active = VIsual_active;

    /*
     * loop through the cursorbound windows
     */
    VIsual_select = VIsual_active = 0;
    FOR_ALL_WINDOWS(curwin)
    {
	curbuf = curwin->w_buffer;
	// skip original window  and windows with 'noscrollbind'
	if (curwin != old_curwin && curwin->w_p_crb)
	{
# ifdef FEAT_DIFF
	    if (curwin->w_p_diff)
		curwin->w_cursor.lnum =
				 diff_get_corresponding_line(old_curbuf, line);
	    else
# endif
		curwin->w_cursor.lnum = line;
	    curwin->w_cursor.col = col;
	    curwin->w_cursor.coladd = coladd;
	    curwin->w_curswant = curswant;
	    curwin->w_set_curswant = set_curswant;

	    // Make sure the cursor is in a valid position.  Temporarily set
	    // "restart_edit" to allow the cursor to be beyond the EOL.
	    restart_edit_save = restart_edit;
	    restart_edit = TRUE;
	    check_cursor();
# ifdef FEAT_SYN_HL
	    if (curwin->w_p_cul || curwin->w_p_cuc)
		validate_cursor();
# endif
	    restart_edit = restart_edit_save;
	    // Correct cursor for multi-byte character.
	    if (has_mbyte)
		mb_adjust_cursor();
	    redraw_later(VALID);

	    // Only scroll when 'scrollbind' hasn't done this.
	    if (!curwin->w_p_scb)
		update_topline();
	    curwin->w_redr_status = TRUE;
	}
    }

    /*
     * reset current-window
     */
    VIsual_select = old_VIsual_select;
    VIsual_active = old_VIsual_active;
    curwin = old_curwin;
    curbuf = old_curbuf;
}

Project: vim
File: move.c

reset_cursorline(void)
{
    curwin->w_last_cursorline = 0;
}

Project: vim
File: move.c

textpos2screenpos(
	win_T	*wp,
	pos_T	*pos,
	int	*rowp,	// screen row
	int	*scolp,	// start screen column
	int	*ccolp,	// cursor screen column
	int	*ecolp)	// end screen column
{
    colnr_T	scol = 0, ccol = 0, ecol = 0;
    int		row = 0;
    int		rowoff = 0;
    colnr_T	coloff = 0;

    if (pos->lnum >= wp->w_topline && pos->lnum <= wp->w_botline)
    {
	colnr_T off;
	colnr_T col;
	int     width;

	row = plines_m_win(wp, wp->w_topline, pos->lnum - 1) + 1;
	getvcol(wp, pos, &scol, &ccol, &ecol);

	// similar to what is done in validate_cursor_col()
	col = scol;
	off = win_col_off(wp);
	col += off;
	width = wp->w_width - off + win_col_off2(wp);

	// long line wrapping, adjust row
	if (wp->w_p_wrap
		&& col >= (colnr_T)wp->w_width
		&& width > 0)
	{
	    // use same formula as what is used in curs_columns()
	    rowoff = ((col - wp->w_width) / width + 1);
	    col -= rowoff * width;
	}
	col -= wp->w_leftcol;
	if (col >= wp->w_width)
	    col = -1;
	if (col >= 0 && row + rowoff <= wp->w_height)
	    coloff = col - scol + wp->w_wincol + 1;
	else
	    // character is left, right or below of the window
	    row = rowoff = scol = ccol = ecol = 0;
    }
    *rowp = W_WINROW(wp) + row + rowoff;
    *scolp = scol + coloff;
    *ccolp = ccol + coloff;
    *ecolp = ecol + coloff;
}

Project: vim
File: move.c

scroll_cursor_bot(int min_scroll, int set_topbot)
{
    int		used;
    int		scrolled = 0;
    int		extra = 0;
    int		i;
    linenr_T	line_count;
    linenr_T	old_topline = curwin->w_topline;
    lineoff_T	loff;
    lineoff_T	boff;
#ifdef FEAT_DIFF
    int		old_topfill = curwin->w_topfill;
    int		fill_below_window;
#endif
    linenr_T	old_botline = curwin->w_botline;
    linenr_T	old_valid = curwin->w_valid;
    int		old_empty_rows = curwin->w_empty_rows;
    linenr_T	cln;		    // Cursor Line Number
    long        so = get_scrolloff_value();

    cln = curwin->w_cursor.lnum;
    if (set_topbot)
    {
	used = 0;
	curwin->w_botline = cln + 1;
#ifdef FEAT_DIFF
	loff.fill = 0;
#endif
	for (curwin->w_topline = curwin->w_botline;
		curwin->w_topline > 1;
		curwin->w_topline = loff.lnum)
	{
	    loff.lnum = curwin->w_topline;
	    topline_back(&loff);
	    if (loff.height == MAXCOL || used + loff.height > curwin->w_height)
		break;
	    used += loff.height;
#ifdef FEAT_DIFF
	    curwin->w_topfill = loff.fill;
#endif
	}
	set_empty_rows(curwin, used);
	curwin->w_valid |= VALID_BOTLINE|VALID_BOTLINE_AP;
	if (curwin->w_topline != old_topline
#ifdef FEAT_DIFF
		|| curwin->w_topfill != old_topfill
#endif
		)
	    curwin->w_valid &= ~(VALID_WROW|VALID_CROW);
    }
    else
	validate_botline();

    // The lines of the cursor line itself are always used.
#ifdef FEAT_DIFF
    used = plines_nofill(cln);
#else
    validate_cheight();
    used = curwin->w_cline_height;
#endif

    // If the cursor is below botline, we will at least scroll by the height
    // of the cursor line.  Correct for empty lines, which are really part of
    // botline.
    if (cln >= curwin->w_botline)
    {
	scrolled = used;
	if (cln == curwin->w_botline)
	    scrolled -= curwin->w_empty_rows;
    }

    /*
     * Stop counting lines to scroll when
     * - hitting start of the file
     * - scrolled nothing or at least 'sj' lines
     * - at least 'scrolloff' lines below the cursor
     * - lines between botline and cursor have been counted
     */
#ifdef FEAT_FOLDING
    if (!hasFolding(curwin->w_cursor.lnum, &loff.lnum, &boff.lnum))
#endif
    {
	loff.lnum = cln;
	boff.lnum = cln;
    }
#ifdef FEAT_DIFF
    loff.fill = 0;
    boff.fill = 0;
    fill_below_window = diff_check_fill(curwin, curwin->w_botline)
						      - curwin->w_filler_rows;
#endif

    while (loff.lnum > 1)
    {
	// Stop when scrolled nothing or at least "min_scroll", found "extra"
	// context for 'scrolloff' and counted all lines below the window.
	if ((((scrolled <= 0 || scrolled >= min_scroll)
		    && extra >= (mouse_dragging > 0 ? mouse_dragging - 1 : so))
		    || boff.lnum + 1 > curbuf->b_ml.ml_line_count)
		&& loff.lnum <= curwin->w_botline
#ifdef FEAT_DIFF
		&& (loff.lnum < curwin->w_botline
		    || loff.fill >= fill_below_window)
#endif
		)
	    break;

	// Add one line above
	topline_back(&loff);
	if (loff.height == MAXCOL)
	    used = MAXCOL;
	else
	    used += loff.height;
	if (used > curwin->w_height)
	    break;
	if (loff.lnum >= curwin->w_botline
#ifdef FEAT_DIFF
		&& (loff.lnum > curwin->w_botline
		    || loff.fill <= fill_below_window)
#endif
		)
	{
	    // Count screen lines that are below the window.
	    scrolled += loff.height;
	    if (loff.lnum == curwin->w_botline
#ifdef FEAT_DIFF
			    && loff.fill == 0
#endif
		    )
		scrolled -= curwin->w_empty_rows;
	}

	if (boff.lnum < curbuf->b_ml.ml_line_count)
	{
	    // Add one line below
	    botline_forw(&boff);
	    used += boff.height;
	    if (used > curwin->w_height)
		break;
	    if (extra < ( mouse_dragging > 0 ? mouse_dragging - 1 : so)
		    || scrolled < min_scroll)
	    {
		extra += boff.height;
		if (boff.lnum >= curwin->w_botline
#ifdef FEAT_DIFF
			|| (boff.lnum + 1 == curwin->w_botline
			    && boff.fill > curwin->w_filler_rows)
#endif
		   )
		{
		    // Count screen lines that are below the window.
		    scrolled += boff.height;
		    if (boff.lnum == curwin->w_botline
#ifdef FEAT_DIFF
			    && boff.fill == 0
#endif
			    )
			scrolled -= curwin->w_empty_rows;
		}
	    }
	}
    }

    // curwin->w_empty_rows is larger, no need to scroll
    if (scrolled <= 0)
	line_count = 0;
    // more than a screenfull, don't scroll but redraw
    else if (used > curwin->w_height)
	line_count = used;
    // scroll minimal number of lines
    else
    {
	line_count = 0;
#ifdef FEAT_DIFF
	boff.fill = curwin->w_topfill;
#endif
	boff.lnum = curwin->w_topline - 1;
	for (i = 0; i < scrolled && boff.lnum < curwin->w_botline; )
	{
	    botline_forw(&boff);
	    i += boff.height;
	    ++line_count;
	}
	if (i < scrolled)	// below curwin->w_botline, don't scroll
	    line_count = 9999;
    }

    /*
     * Scroll up if the cursor is off the bottom of the screen a bit.
     * Otherwise put it at 1/2 of the screen.
     */
    if (line_count >= curwin->w_height && line_count > min_scroll)
	scroll_cursor_halfway(FALSE);
    else
	scrollup(line_count, TRUE);

    /*
     * If topline didn't change we need to restore w_botline and w_empty_rows
     * (we changed them).
     * If topline did change, update_screen() will set botline.
     */
    if (curwin->w_topline == old_topline && set_topbot)
    {
	curwin->w_botline = old_botline;
	curwin->w_empty_rows = old_empty_rows;
	curwin->w_valid = old_valid;
    }
    curwin->w_valid |= VALID_TOPLINE;
}

Project: vim
File: move.c

update_topline(void)
{
    long	line_count;
    int		halfheight;
    int		n;
    linenr_T	old_topline;
#ifdef FEAT_DIFF
    int		old_topfill;
#endif
#ifdef FEAT_FOLDING
    linenr_T	lnum;
#endif
    int		check_topline = FALSE;
    int		check_botline = FALSE;
    long        *so_ptr = curwin->w_p_so >= 0 ? &curwin->w_p_so : &p_so;
    int		save_so = *so_ptr;

    // If there is no valid screen and when the window height is zero just use
    // the cursor line.
    if (!screen_valid(TRUE) || curwin->w_height == 0)
    {
	check_cursor_lnum();
	curwin->w_topline = curwin->w_cursor.lnum;
	curwin->w_botline = curwin->w_topline;
	curwin->w_scbind_pos = 1;
	return;
    }

    check_cursor_moved(curwin);
    if (curwin->w_valid & VALID_TOPLINE)
	return;

    // When dragging with the mouse, don't scroll that quickly
    if (mouse_dragging > 0)
	*so_ptr = mouse_dragging - 1;

    old_topline = curwin->w_topline;
#ifdef FEAT_DIFF
    old_topfill = curwin->w_topfill;
#endif

    /*
     * If the buffer is empty, always set topline to 1.
     */
    if (BUFEMPTY())		// special case - file is empty
    {
	if (curwin->w_topline != 1)
	    redraw_later(NOT_VALID);
	curwin->w_topline = 1;
	curwin->w_botline = 2;
	curwin->w_valid |= VALID_BOTLINE|VALID_BOTLINE_AP;
	curwin->w_scbind_pos = 1;
    }

    /*
     * If the cursor is above or near the top of the window, scroll the window
     * to show the line the cursor is in, with 'scrolloff' context.
     */
    else
    {
	if (curwin->w_topline > 1)
	{
	    // If the cursor is above topline, scrolling is always needed.
	    // If the cursor is far below topline and there is no folding,
	    // scrolling down is never needed.
	    if (curwin->w_cursor.lnum < curwin->w_topline)
		check_topline = TRUE;
	    else if (check_top_offset())
		check_topline = TRUE;
	}
#ifdef FEAT_DIFF
	    // Check if there are more filler lines than allowed.
	if (!check_topline && curwin->w_topfill > diff_check_fill(curwin,
							   curwin->w_topline))
	    check_topline = TRUE;
#endif

	if (check_topline)
	{
	    halfheight = curwin->w_height / 2 - 1;
	    if (halfheight < 2)
		halfheight = 2;

#ifdef FEAT_FOLDING
	    if (hasAnyFolding(curwin))
	    {
		// Count the number of logical lines between the cursor and
		// topline + scrolloff (approximation of how much will be
		// scrolled).
		n = 0;
		for (lnum = curwin->w_cursor.lnum;
				    lnum < curwin->w_topline + *so_ptr; ++lnum)
		{
		    ++n;
		    // stop at end of file or when we know we are far off
		    if (lnum >= curbuf->b_ml.ml_line_count || n >= halfheight)
			break;
		    (void)hasFolding(lnum, NULL, &lnum);
		}
	    }
	    else
#endif
		n = curwin->w_topline + *so_ptr - curwin->w_cursor.lnum;

	    // If we weren't very close to begin with, we scroll to put the
	    // cursor in the middle of the window.  Otherwise put the cursor
	    // near the top of the window.
	    if (n >= halfheight)
		scroll_cursor_halfway(FALSE);
	    else
	    {
		scroll_cursor_top(scrolljump_value(), FALSE);
		check_botline = TRUE;
	    }
	}

	else
	{
#ifdef FEAT_FOLDING
	    // Make sure topline is the first line of a fold.
	    (void)hasFolding(curwin->w_topline, &curwin->w_topline, NULL);
#endif
	    check_botline = TRUE;
	}
    }

    /*
     * If the cursor is below the bottom of the window, scroll the window
     * to put the cursor on the window.
     * When w_botline is invalid, recompute it first, to avoid a redraw later.
     * If w_botline was approximated, we might need a redraw later in a few
     * cases, but we don't want to spend (a lot of) time recomputing w_botline
     * for every small change.
     */
    if (check_botline)
    {
	if (!(curwin->w_valid & VALID_BOTLINE_AP))
	    validate_botline();

	if (curwin->w_botline <= curbuf->b_ml.ml_line_count)
	{
	    if (curwin->w_cursor.lnum < curwin->w_botline)
	    {
	      if (((long)curwin->w_cursor.lnum
					     >= (long)curwin->w_botline - *so_ptr
#ifdef FEAT_FOLDING
			|| hasAnyFolding(curwin)
#endif
			))
	      {
		lineoff_T	loff;

		// Cursor is (a few lines) above botline, check if there are
		// 'scrolloff' window lines below the cursor.  If not, need to
		// scroll.
		n = curwin->w_empty_rows;
		loff.lnum = curwin->w_cursor.lnum;
#ifdef FEAT_FOLDING
		// In a fold go to its last line.
		(void)hasFolding(loff.lnum, NULL, &loff.lnum);
#endif
#ifdef FEAT_DIFF
		loff.fill = 0;
		n += curwin->w_filler_rows;
#endif
		loff.height = 0;
		while (loff.lnum < curwin->w_botline
#ifdef FEAT_DIFF
			&& (loff.lnum + 1 < curwin->w_botline || loff.fill == 0)
#endif
			)
		{
		    n += loff.height;
		    if (n >= *so_ptr)
			break;
		    botline_forw(&loff);
		}
		if (n >= *so_ptr)
		    // sufficient context, no need to scroll
		    check_botline = FALSE;
	      }
	      else
		  // sufficient context, no need to scroll
		  check_botline = FALSE;
	    }
	    if (check_botline)
	    {
#ifdef FEAT_FOLDING
		if (hasAnyFolding(curwin))
		{
		    // Count the number of logical lines between the cursor and
		    // botline - scrolloff (approximation of how much will be
		    // scrolled).
		    line_count = 0;
		    for (lnum = curwin->w_cursor.lnum;
				   lnum >= curwin->w_botline - *so_ptr; --lnum)
		    {
			++line_count;
			// stop at end of file or when we know we are far off
			if (lnum <= 0 || line_count > curwin->w_height + 1)
			    break;
			(void)hasFolding(lnum, &lnum, NULL);
		    }
		}
		else
#endif
		    line_count = curwin->w_cursor.lnum - curwin->w_botline
								   + 1 + *so_ptr;
		if (line_count <= curwin->w_height + 1)
		    scroll_cursor_bot(scrolljump_value(), FALSE);
		else
		    scroll_cursor_halfway(FALSE);
	    }
	}
    }
    curwin->w_valid |= VALID_TOPLINE;

    /*
     * Need to redraw when topline changed.
     */
    if (curwin->w_topline != old_topline
#ifdef FEAT_DIFF
	    || curwin->w_topfill != old_topfill
#endif
	    )
    {
	dollar_vcol = -1;
	if (curwin->w_skipcol != 0)
	{
	    curwin->w_skipcol = 0;
	    redraw_later(NOT_VALID);
	}
	else
	    redraw_later(VALID);
	// May need to set w_skipcol when cursor in w_topline.
	if (curwin->w_cursor.lnum == curwin->w_topline)
	    validate_cursor();
    }

    *so_ptr = save_so;
}

Project: vim
File: move.c

halfpage(int flag, linenr_T Prenum)
{
    long	scrolled = 0;
    int		i;
    int		n;
    int		room;

    if (Prenum)
	curwin->w_p_scr = (Prenum > curwin->w_height) ?
						curwin->w_height : Prenum;
    n = (curwin->w_p_scr <= curwin->w_height) ?
				    curwin->w_p_scr : curwin->w_height;

    update_topline();
    validate_botline();
    room = curwin->w_empty_rows;
#ifdef FEAT_DIFF
    room += curwin->w_filler_rows;
#endif
    if (flag)
    {
	/*
	 * scroll the text up
	 */
	while (n > 0 && curwin->w_botline <= curbuf->b_ml.ml_line_count)
	{
#ifdef FEAT_DIFF
	    if (curwin->w_topfill > 0)
	    {
		i = 1;
		--n;
		--curwin->w_topfill;
	    }
	    else
#endif
	    {
		i = PLINES_NOFILL(curwin->w_topline);
		n -= i;
		if (n < 0 && scrolled > 0)
		    break;
#ifdef FEAT_FOLDING
		(void)hasFolding(curwin->w_topline, NULL, &curwin->w_topline);
#endif
		++curwin->w_topline;
#ifdef FEAT_DIFF
		curwin->w_topfill = diff_check_fill(curwin, curwin->w_topline);
#endif

		if (curwin->w_cursor.lnum < curbuf->b_ml.ml_line_count)
		{
		    ++curwin->w_cursor.lnum;
		    curwin->w_valid &=
				    ~(VALID_VIRTCOL|VALID_CHEIGHT|VALID_WCOL);
		}
	    }
	    curwin->w_valid &= ~(VALID_CROW|VALID_WROW);
	    scrolled += i;

	    /*
	     * Correct w_botline for changed w_topline.
	     * Won't work when there are filler lines.
	     */
#ifdef FEAT_DIFF
	    if (curwin->w_p_diff)
		curwin->w_valid &= ~(VALID_BOTLINE|VALID_BOTLINE_AP);
	    else
#endif
	    {
		room += i;
		do
		{
		    i = plines(curwin->w_botline);
		    if (i > room)
			break;
#ifdef FEAT_FOLDING
		    (void)hasFolding(curwin->w_botline, NULL,
							  &curwin->w_botline);
#endif
		    ++curwin->w_botline;
		    room -= i;
		} while (curwin->w_botline <= curbuf->b_ml.ml_line_count);
	    }
	}

	/*
	 * When hit bottom of the file: move cursor down.
	 */
	if (n > 0)
	{
# ifdef FEAT_FOLDING
	    if (hasAnyFolding(curwin))
	    {
		while (--n >= 0
			&& curwin->w_cursor.lnum < curbuf->b_ml.ml_line_count)
		{
		    (void)hasFolding(curwin->w_cursor.lnum, NULL,
						      &curwin->w_cursor.lnum);
		    ++curwin->w_cursor.lnum;
		}
	    }
	    else
# endif
		curwin->w_cursor.lnum += n;
	    check_cursor_lnum();
	}
    }
    else
    {
	/*
	 * scroll the text down
	 */
	while (n > 0 && curwin->w_topline > 1)
	{
#ifdef FEAT_DIFF
	    if (curwin->w_topfill < diff_check_fill(curwin, curwin->w_topline))
	    {
		i = 1;
		--n;
		++curwin->w_topfill;
	    }
	    else
#endif
	    {
		i = PLINES_NOFILL(curwin->w_topline - 1);
		n -= i;
		if (n < 0 && scrolled > 0)
		    break;
		--curwin->w_topline;
#ifdef FEAT_FOLDING
		(void)hasFolding(curwin->w_topline, &curwin->w_topline, NULL);
#endif
#ifdef FEAT_DIFF
		curwin->w_topfill = 0;
#endif
	    }
	    curwin->w_valid &= ~(VALID_CROW|VALID_WROW|
					      VALID_BOTLINE|VALID_BOTLINE_AP);
	    scrolled += i;
	    if (curwin->w_cursor.lnum > 1)
	    {
		--curwin->w_cursor.lnum;
		curwin->w_valid &= ~(VALID_VIRTCOL|VALID_CHEIGHT|VALID_WCOL);
	    }
	}

	/*
	 * When hit top of the file: move cursor up.
	 */
	if (n > 0)
	{
	    if (curwin->w_cursor.lnum <= (linenr_T)n)
		curwin->w_cursor.lnum = 1;
	    else
# ifdef FEAT_FOLDING
	    if (hasAnyFolding(curwin))
	    {
		while (--n >= 0 && curwin->w_cursor.lnum > 1)
		{
		    --curwin->w_cursor.lnum;
		    (void)hasFolding(curwin->w_cursor.lnum,
						&curwin->w_cursor.lnum, NULL);
		}
	    }
	    else
# endif
		curwin->w_cursor.lnum -= n;
	}
    }
# ifdef FEAT_FOLDING
    // Move cursor to first line of closed fold.
    foldAdjustCursor();
# endif
#ifdef FEAT_DIFF
    check_topfill(curwin, !flag);
#endif
    cursor_correct();
    beginline(BL_SOL | BL_FIX);
    redraw_later(VALID);
}

Project: vim
File: move.c

update_curswant(void)
{
    if (curwin->w_set_curswant)
    {
	validate_virtcol();
	curwin->w_curswant = curwin->w_virtcol;
	curwin->w_set_curswant = FALSE;
    }
}

Project: vim
File: move.c

f_screenpos(typval_T *argvars UNUSED, typval_T *rettv)
{
    dict_T	*dict;
    win_T	*wp;
    pos_T	pos;
    int		row = 0;
    int		scol = 0, ccol = 0, ecol = 0;

    if (rettv_dict_alloc(rettv) != OK)
	return;
    dict = rettv->vval.v_dict;

    if (in_vim9script()
	    && (check_for_number_arg(argvars, 0) == FAIL
		|| check_for_number_arg(argvars, 1) == FAIL
		|| check_for_number_arg(argvars, 2) == FAIL))
	return;

    wp = find_win_by_nr_or_id(&argvars[0]);
    if (wp == NULL)
	return;

    pos.lnum = tv_get_number(&argvars[1]);
    pos.col = tv_get_number(&argvars[2]) - 1;
    pos.coladd = 0;
    textpos2screenpos(wp, &pos, &row, &scol, &ccol, &ecol);

    dict_add_number(dict, "row", row);
    dict_add_number(dict, "col", scol);
    dict_add_number(dict, "curscol", ccol);
    dict_add_number(dict, "endcol", ecol);
}

Project: vim
File: move.c

cursor_correct(void)
{
    int		above = 0;	    // screen lines above topline
    linenr_T	topline;
    int		below = 0;	    // screen lines below botline
    linenr_T	botline;
    int		above_wanted, below_wanted;
    linenr_T	cln;		    // Cursor Line Number
    int		max_off;
    long        so = get_scrolloff_value();

    /*
     * How many lines we would like to have above/below the cursor depends on
     * whether the first/last line of the file is on screen.
     */
    above_wanted = so;
    below_wanted = so;
    if (mouse_dragging > 0)
    {
	above_wanted = mouse_dragging - 1;
	below_wanted = mouse_dragging - 1;
    }
    if (curwin->w_topline == 1)
    {
	above_wanted = 0;
	max_off = curwin->w_height / 2;
	if (below_wanted > max_off)
	    below_wanted = max_off;
    }
    validate_botline();
    if (curwin->w_botline == curbuf->b_ml.ml_line_count + 1
	    && mouse_dragging == 0)
    {
	below_wanted = 0;
	max_off = (curwin->w_height - 1) / 2;
	if (above_wanted > max_off)
	    above_wanted = max_off;
    }

    /*
     * If there are sufficient file-lines above and below the cursor, we can
     * return now.
     */
    cln = curwin->w_cursor.lnum;
    if (cln >= curwin->w_topline + above_wanted
	    && cln < curwin->w_botline - below_wanted
#ifdef FEAT_FOLDING
	    && !hasAnyFolding(curwin)
#endif
	    )
	return;

    /*
     * Narrow down the area where the cursor can be put by taking lines from
     * the top and the bottom until:
     * - the desired context lines are found
     * - the lines from the top is past the lines from the bottom
     */
    topline = curwin->w_topline;
    botline = curwin->w_botline - 1;
#ifdef FEAT_DIFF
    // count filler lines as context
    above = curwin->w_topfill;
    below = curwin->w_filler_rows;
#endif
    while ((above < above_wanted || below < below_wanted) && topline < botline)
    {
	if (below < below_wanted && (below <= above || above >= above_wanted))
	{
#ifdef FEAT_FOLDING
	    if (hasFolding(botline, &botline, NULL))
		++below;
	    else
#endif
		below += plines(botline);
	    --botline;
	}
	if (above < above_wanted && (above < below || below >= below_wanted))
	{
#ifdef FEAT_FOLDING
	    if (hasFolding(topline, NULL, &topline))
		++above;
	    else
#endif
		above += PLINES_NOFILL(topline);
#ifdef FEAT_DIFF
	    // Count filler lines below this line as context.
	    if (topline < botline)
		above += diff_check_fill(curwin, topline + 1);
#endif
	    ++topline;
	}
    }
    if (topline == botline || botline == 0)
	curwin->w_cursor.lnum = topline;
    else if (topline > botline)
	curwin->w_cursor.lnum = botline;
    else
    {
	if (cln < topline && curwin->w_topline > 1)
	{
	    curwin->w_cursor.lnum = topline;
	    curwin->w_valid &=
			    ~(VALID_WROW|VALID_WCOL|VALID_CHEIGHT|VALID_CROW);
	}
	if (cln > botline && curwin->w_botline <= curbuf->b_ml.ml_line_count)
	{
	    curwin->w_cursor.lnum = botline;
	    curwin->w_valid &=
			    ~(VALID_WROW|VALID_WCOL|VALID_CHEIGHT|VALID_CROW);
	}
    }
    curwin->w_valid |= VALID_TOPLINE;
}

Project: vim
File: move.c

onepage(int dir, long count)
{
    long	n;
    int		retval = OK;
    lineoff_T	loff;
    linenr_T	old_topline = curwin->w_topline;
    long        so = get_scrolloff_value();

    if (curbuf->b_ml.ml_line_count == 1)    // nothing to do
    {
	beep_flush();
	return FAIL;
    }

    for ( ; count > 0; --count)
    {
	validate_botline();
	/*
	 * It's an error to move a page up when the first line is already on
	 * the screen.	It's an error to move a page down when the last line
	 * is on the screen and the topline is 'scrolloff' lines from the
	 * last line.
	 */
	if (dir == FORWARD
		? ((curwin->w_topline >= curbuf->b_ml.ml_line_count - so)
		    && curwin->w_botline > curbuf->b_ml.ml_line_count)
		: (curwin->w_topline == 1
#ifdef FEAT_DIFF
		    && curwin->w_topfill ==
				    diff_check_fill(curwin, curwin->w_topline)
#endif
		    ))
	{
	    beep_flush();
	    retval = FAIL;
	    break;
	}

#ifdef FEAT_DIFF
	loff.fill = 0;
#endif
	if (dir == FORWARD)
	{
	    if (ONE_WINDOW && p_window > 0 && p_window < Rows - 1)
	    {
		// Vi compatible scrolling
		if (p_window <= 2)
		    ++curwin->w_topline;
		else
		    curwin->w_topline += p_window - 2;
		if (curwin->w_topline > curbuf->b_ml.ml_line_count)
		    curwin->w_topline = curbuf->b_ml.ml_line_count;
		curwin->w_cursor.lnum = curwin->w_topline;
	    }
	    else if (curwin->w_botline > curbuf->b_ml.ml_line_count)
	    {
		// at end of file
		curwin->w_topline = curbuf->b_ml.ml_line_count;
#ifdef FEAT_DIFF
		curwin->w_topfill = 0;
#endif
		curwin->w_valid &= ~(VALID_WROW|VALID_CROW);
	    }
	    else
	    {
		// For the overlap, start with the line just below the window
		// and go upwards.
		loff.lnum = curwin->w_botline;
#ifdef FEAT_DIFF
		loff.fill = diff_check_fill(curwin, loff.lnum)
						      - curwin->w_filler_rows;
#endif
		get_scroll_overlap(&loff, -1);
		curwin->w_topline = loff.lnum;
#ifdef FEAT_DIFF
		curwin->w_topfill = loff.fill;
		check_topfill(curwin, FALSE);
#endif
		curwin->w_cursor.lnum = curwin->w_topline;
		curwin->w_valid &= ~(VALID_WCOL|VALID_CHEIGHT|VALID_WROW|
				   VALID_CROW|VALID_BOTLINE|VALID_BOTLINE_AP);
	    }
	}
	else	// dir == BACKWARDS
	{
#ifdef FEAT_DIFF
	    if (curwin->w_topline == 1)
	    {
		// Include max number of filler lines
		max_topfill();
		continue;
	    }
#endif
	    if (ONE_WINDOW && p_window > 0 && p_window < Rows - 1)
	    {
		// Vi compatible scrolling (sort of)
		if (p_window <= 2)
		    --curwin->w_topline;
		else
		    curwin->w_topline -= p_window - 2;
		if (curwin->w_topline < 1)
		    curwin->w_topline = 1;
		curwin->w_cursor.lnum = curwin->w_topline + p_window - 1;
		if (curwin->w_cursor.lnum > curbuf->b_ml.ml_line_count)
		    curwin->w_cursor.lnum = curbuf->b_ml.ml_line_count;
		continue;
	    }

	    // Find the line at the top of the window that is going to be the
	    // line at the bottom of the window.  Make sure this results in
	    // the same line as before doing CTRL-F.
	    loff.lnum = curwin->w_topline - 1;
#ifdef FEAT_DIFF
	    loff.fill = diff_check_fill(curwin, loff.lnum + 1)
							  - curwin->w_topfill;
#endif
	    get_scroll_overlap(&loff, 1);

	    if (loff.lnum >= curbuf->b_ml.ml_line_count)
	    {
		loff.lnum = curbuf->b_ml.ml_line_count;
#ifdef FEAT_DIFF
		loff.fill = 0;
	    }
	    else
	    {
		botline_topline(&loff);
#endif
	    }
	    curwin->w_cursor.lnum = loff.lnum;

	    // Find the line just above the new topline to get the right line
	    // at the bottom of the window.
	    n = 0;
	    while (n <= curwin->w_height && loff.lnum >= 1)
	    {
		topline_back(&loff);
		if (loff.height == MAXCOL)
		    n = MAXCOL;
		else
		    n += loff.height;
	    }
	    if (loff.lnum < 1)			// at begin of file
	    {
		curwin->w_topline = 1;
#ifdef FEAT_DIFF
		max_topfill();
#endif
		curwin->w_valid &= ~(VALID_WROW|VALID_CROW|VALID_BOTLINE);
	    }
	    else
	    {
		// Go two lines forward again.
#ifdef FEAT_DIFF
		topline_botline(&loff);
#endif
		botline_forw(&loff);
		botline_forw(&loff);
#ifdef FEAT_DIFF
		botline_topline(&loff);
#endif
#ifdef FEAT_FOLDING
		// We're at the wrong end of a fold now.
		(void)hasFolding(loff.lnum, &loff.lnum, NULL);
#endif

		// Always scroll at least one line.  Avoid getting stuck on
		// very long lines.
		if (loff.lnum >= curwin->w_topline
#ifdef FEAT_DIFF
			&& (loff.lnum > curwin->w_topline
			    || loff.fill >= curwin->w_topfill)
#endif
			)
		{
#ifdef FEAT_DIFF
		    // First try using the maximum number of filler lines.  If
		    // that's not enough, backup one line.
		    loff.fill = curwin->w_topfill;
		    if (curwin->w_topfill < diff_check_fill(curwin,
							   curwin->w_topline))
			max_topfill();
		    if (curwin->w_topfill == loff.fill)
#endif
		    {
			--curwin->w_topline;
#ifdef FEAT_DIFF
			curwin->w_topfill = 0;
#endif
		    }
		    comp_botline(curwin);
		    curwin->w_cursor.lnum = curwin->w_botline - 1;
		    curwin->w_valid &=
			    ~(VALID_WCOL|VALID_CHEIGHT|VALID_WROW|VALID_CROW);
		}
		else
		{
		    curwin->w_topline = loff.lnum;
#ifdef FEAT_DIFF
		    curwin->w_topfill = loff.fill;
		    check_topfill(curwin, FALSE);
#endif
		    curwin->w_valid &= ~(VALID_WROW|VALID_CROW|VALID_BOTLINE);
		}
	    }
	}
    }
#ifdef FEAT_FOLDING
    foldAdjustCursor();
#endif
    cursor_correct();
    check_cursor_col();
    if (retval == OK)
	beginline(BL_SOL | BL_FIX);
    curwin->w_valid &= ~(VALID_WCOL|VALID_WROW|VALID_VIRTCOL);

    if (retval == OK && dir == FORWARD)
    {
	// Avoid the screen jumping up and down when 'scrolloff' is non-zero.
	// But make sure we scroll at least one line (happens with mix of long
	// wrapping lines and non-wrapping line).
	if (check_top_offset())
	{
	    scroll_cursor_top(1, FALSE);
	    if (curwin->w_topline <= old_topline
				  && old_topline < curbuf->b_ml.ml_line_count)
	    {
		curwin->w_topline = old_topline + 1;
#ifdef FEAT_FOLDING
		(void)hasFolding(curwin->w_topline, &curwin->w_topline, NULL);
#endif
	    }
	}
#ifdef FEAT_FOLDING
	else if (curwin->w_botline > curbuf->b_ml.ml_line_count)
	    (void)hasFolding(curwin->w_topline, &curwin->w_topline, NULL);
#endif
    }

    redraw_later(VALID);
    return retval;
}

Project: vim
File: move.c

validate_virtcol_win(win_T *wp)
{
    check_cursor_moved(wp);
    if (!(wp->w_valid & VALID_VIRTCOL))
    {
	getvvcol(wp, &wp->w_cursor, NULL, &(wp->w_virtcol), NULL);
	wp->w_valid |= VALID_VIRTCOL;
#ifdef FEAT_SYN_HL
	if (wp->w_p_cuc && !pum_visible())
	    redraw_win_later(wp, SOME_VALID);
#endif
    }
}